Effects of alendronate in bone repair: A study in rat femur fractures treated with plates and screws

Abstract

Background Alendronate (ALN) has direct action on bone metabolism, increasing osteogenesis and decreasing bone resorption. The study rated the effect of ALN on femoral fracture repair and the effect of different doses of the drug on the liver and kidneys. Methods Wistar rats were divided into groups: A1 (ALN 1 mg/kg), A2 (ALN 3 mg/kg), and C (saline solution). The drug/solution was applied intraperitoneally three times a week after femoral fracture until euthanasia 45 days later. Results Liver analysis from group A1 presented normal histological aspects, while hepatic steatosis was observed in group A2. In groups A1 and A2, kidneys showed amylocymile like cell degeneration. In femur bone callus, no difference was observed in collagens I and III or in number of trabeculae (p ≥ 0.05). Immunohistochemical evaluation showed positivity for the Transforming Grow Factor β-1 (TGFβ-1) marker in the control group, in spinal area and in small chondrocytes, but negativity for hypertrophy. In A1, an extensive area of cartilaginous expansion was observed, with positive hypertrophic TGFβ-1 cartilage, even in areas with bone matrix. A low positivity was observed in the medullar area, in contrast to the control. Group A2 presented a high number of chondroid matrices and a moderate number of TGFβ-1 cells, with little positivity in medullary area. Conclusions A dosage of ALN 1 mg/kg promotes cellular differentiation activity in the bone callus region, with mild damage in the liver and kidneys. A dosage of ALN 3 mg/kg became toxic without positive alterations in cell differentiation.